In recent years, organic semiconductor illumination devices, e.g. organic light emitting diode (OLED) devices, have been remarkably researched and developed as light sources of green energy in illumination industry. Sourced from various materials without containing noxious substances, such as mercury, the organic semiconductor illumination devices are friendly to environment. In addition, the devices having light-diffusing area sources have advantages of soft light color without the glare, energy conservation, high-efficiency, long service life, no heat, no UV, thin and light configuration, adjustable color temperature and brightness. The devices may be flexible by using flexible substrates.
Limited by current technology, each organic light emitting diode display has an area ranging from 10 cm×10 cm to 30 cm×30 cm. Thus, an organic semiconductor illumination device with a larger area, such as, more than 100 cm×100 cm, must be configured by arranging several organic light emitting diode displays side by side. As shown in FIG. 1, the current organic light emitting diode display 10 has a non-emitting region 101 at a periphery and an emitting region 102 surrounded by the non-emitting region 101. As a plurality of organic light emitting diode displays 10 are arranged side by side to form lightless zones at connecting portions between the displays 10. As shown in FIG. 1, there are many lightless zones on an emitting face of the organic semiconductor illumination device with the larger area.
The above drawbacks may not only impair the appearance of organic semiconductor illumination device, but also reduce the light emission rate thereof. Hence, there is a need to develop a large-area illumination device capable of eliminating the lightless zone, enhancing the appearance and emission rate thereof.